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Ameliorating acidity of an extensively‐managed permanent pasture soil
Author(s) -
Norton M. R.,
Garden D. L.,
Orchard B. A.,
Armstrong P.
Publication year - 2018
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12441
Subject(s) - lime , soil ph , zoology , chemistry , soil water , pasture , stocking , agronomy , soil science , environmental science , biology , paleontology
Acid soil amelioration was measured annually over an 11 year experiment. Lime, and superphosphate were surface‐applied under combinations of three rates of lime, viz. nil, lime to raise pH C a of 0–10 cm to 5.0 (low rate) and 5.5 (high rate) respectively, two rates of superphosphate (125 kg/ha every 2 to 3 yr, 250 kg/ha/yr) and two sheep stocking rates. Soils were sampled at 0–2.5, 2.5–5, 5–7.5, 7.5–10, 10–15 and 15–20 cm. Soil pH stratification developed after lime application. By 11 yr lime had not raised pH C a to either 5.0 or 5.5 in the 5–10 cm profile. However, pH C a >5.0 or >5.5 were observed in the 0–5 cm profile. Under high P, low lime application, soil pH C a was higher in the 0–2.5 cm profile at low stocking rate. Effects of applied lime on pH C a declined with time and depth under low lime and the relationship with Al ex which increased as pH C a declined, was modelled. A rarely reported relationship showed that as soil C increased the apparent solubility of Al decreased. At the lowest pH C a considered, there was a strong negative association between Al ex and total C, becoming weaker with positive pH C a increments. Higher P rates increased pH C a under low lime contrasting with lesser effects on pH C a under low P at the same lime rate. Slow and limited lime movement means that farmers growing acid sensitive plants must apply lime early enough and at rates and frequencies sufficient to ensure downward movement.